Rhamnus cathartica is fairly invasive in the woods around Manhattan, Kansas, but then again it was promoted as a good tree for a while and the birds love the berries - at least there.
Kudzu is NOT invasive in undisturbed woods. It spreads into disturbed woods, but needs heavy disturbance to get established or the helping hand of a non-forward-thinking government. Then it just persists...and persists.
The one problem I see most frequently is Lonicera maackii. It is a hideous weed because the leaves remain on photosynthesizing long after the natives have gone dormant. The birds spread the seeds, it grows quickly and nearly anywhere.
But, lets not call them Asian honeysuckles! There are many very good Lonicera from Asia for the garden and to give the government or anyone any extra reason to ban the whole genus for a few unruly few would be bad. Lonicera x purpusii is considered a noxious weed in TN, but it does not spread by seed because it rarely sets fruit. It persists from plantings and can locally spread by vegetative means and the occasional seed.
Aaron
--- On Thu, 3/18/10, Dennis Kramb <dkramb@badbear.com> wrote:
From: Dennis Kramb <dkramb@badbear.com>
Subject: Re: [pbs] Legacy bulbs-desirable plants or weeds
To: "Pacific Bulb Society" <pbs@lists.ibiblio.org>
Date: Thursday, March 18, 2010, 2:42 AM
The integrity of the local native environment can play a large factor in
invasiveness of an exotic species.
For example in Cincinnati the asian honeysuckles are an absolute menace.
But a few counties over where the native forest remains largely intact and
unfragmented, the honeysuckles are not invasive at all. The healthy
undisturbed native forest ecosystem holds them in check. But in suburbia
where I live they are a major pest and headache.
To the south, I think kudzu is rampant even in intact forests.... so.... as
Boyce says it's a complex interaction!